He was a German physiologist who, along with Matthias Schleiden, formulated the cell theory in 1839. This theory states that:
1. All living organisms are composed of one or more cells.
2. The cell is the basic unit of structure and organization in organisms.
3. All cells arise from pre-existing cells.
While Schleiden focused on plant cells, Schwann extended the theory to animal cells, after observing that both animal and plant tissues were composed of similar building blocks.
